Steering and manoeuvering system for water-born vessels

ABSTRACT

Steering and manoeuvering system for water-borne vessels with two individually turnable propulsion units aranged mutually spaced athwartships in the stern portion of the vessel, and including an actuating turning device (7,8) actuable by a steering control (1), e.g. a lever, such as to maintain the propulsing units parallel during turning in normal sailing of the vehicle ahead or astern, i.e. in the so-called normal steering mode, and an actuating drive device (9,10) for setting the propulsive power and direction ahead/astern of the respective propulsion unit, said drive device being actuable by a power control (2). The system is switchable between said normal steering mode (3) and at least one special manoeuvering mode (4,5), in which the two propulsion units achieve a force resultant directed substantially athwartships for athwartships and/or turning movement of the vessel.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a steering and manoeuvering system forwater-born vessels with two individually turnable propulsion unitsarranged at the stern portion of the vessel and mutually spacedathwartships. These units may be such as jet units, turnable so-calledthrusters or turnable propeller units of the "AQUAMATIC", "Z-DRIVE" typeor the like, (but not propeller units with a stationary propeller shaftand a separate rudder).

2. Prior Art

A first type of known steering and manoeuvering system for vessels withsuch double propulsion units includes an actuating turning device, whichis actuable by a steering control, e.g. a lever or a wheel, and keepsthe propulsion units parallel while being turned, and an actuating drivedevice, which is actuable by a power control for adjusting thepropulsive power ahead or astern of the respective propulsion unit. Thevessel can thus be steered for sailing ahead or astern in a desiredstarboard/port direction, as well as for executing a rotating or turningmovement (one unit set for propulsion ahead and the other one forpropulsion astern) which can be to advantage in manoeuvering in ports,harbours and other cramped situations. It is not possible to achievepure athwartships movement with such a system, however. Athwartshipsmovement namely requires that both propulsion units can be turned inopposite angular directions with opposing directions of propulsion.

In a second type of known steering and manoeuvering system (U.S. Pat.No. 3,976,023) all steering functions are achieved by a singlecontrolling joystick which is movable in two dimensions. When thejoystick is moved forwards/backwards the combined propulsion effect isincreased ahead or astern (by different adjustments of the turningangle) and when the joystick is moved sideways port/starboard steeringaction is achieved to port or starboard. The power of the propulsionunits can be regulated at the same time by pulling out or depressing aknob on the joystick. Turning and athwartships movement of the vesselcan be achieved for certain positions of the joystick.

Such a steering and manoeuvering system can indeed appear to be simple,since only one lever is used, but even so it requires that the steersmanof the vessel with this system is given extensive training in order tomaster different manoeuvres, particularly manoeuvers in harbours andports. In addition, with this system it is difficult to compensate forexternal forces, e.g. those coming from wind and current, which act onthe vessel in a translatory and/or rotary direction.

SUMMARY OF THE INVENTION

The object of the present invention is to achieve a steering andmanoeuvering system of the first type mentioned above, which furthermoreenables a person to execute complicated special manoeuvers after onlyhaving passed a short training course. In normal sailing, it shall thusbe possible to steer the vessel to port or starboard conventionally withthe aid of a control such as a wheel or lever, while the power controlis utilized in a way which is easily understood and natural, from theaspect of logical control, in the execution of special manoeuvers.

This object is achieved by the invention in that the steering andmanoeuvering system includes a function selector with the aid of whichthe system is switchable between a normal steering mode, where thepropulsion units are kept parallel during steering, and at least onespecial manoeuvering mode, where the steering control is disconnectedfrom its normal steering function and said actuating turning device isinstead actuated automatically irrespective of the position of thesteering control for setting the two propulsion units at symmetricalturning angles in opposite directions so that the two propulsion unitsachieve a force resultant directed substantially athwartships forathwartships and/or turning movement of the vessel, while said actuatingdrive device is actuated for setting the two propulsion units inopposing propulsive directions ahead/astern.

By the automatic setting of the angular positions of the propulsionunits in the special manoeuvering mode, the steersman can concentrate onrelatively simple control functions, such as increasing or decreasingthe turning or athwartships movement rate, with the aid of the powercontrol. It has been found that such manoeuvering can be carried outextremely simply, but still exactly and effectively, and since normalsailing takes place conventionally with the aid of the steering andpower controls, the steersman can quickly learn to master the steeringand manoeuvering system in accordance with the invention.

The special manoeuvering modes can suitably be an athwartships movementmode and a turning mode.

In the respective special manoeuvering mode (turning or athwartshipsmovement) the steering control is preferably utilized to adjust theturning angle of the propulsion units such that the turning angles arechanged symmetrically in opposite directions while retaining symmetry,whereby the point of action of the force resultant is moved along thefore and aft line of the vessel or an extension of this line. In theathwartships mode, the steersman can thus readily achieve either acompensating torque, if the vessel is acted on by outside forces as aresult of wind or current, or a superposed turning movement. In theturning mode, such displacement of the force resultant point of actionachieves an amplification of weakening of the torque.

Switching between the different modes is preferably achieved with theaid of a manually settable function selector, particularly a preselectorswitch, which does not switch to the set mode until certain operating ormanoeuvering conditions have been met.

The power control can consist either of a conventional double levercontrol or a special control, which achieves synchronous propulsionpower setting, when it is moved in a first dimension, and powerbalancing by changing the propulsive power in the opposite direction(ahead-astern) of the respective propulsion unit, when it is moved in asecond dimension.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in more detail below with reference tothe accompanying drawings, which illustrate two exemplary embodiments.

FIG. 1A schematically illustrates a power control unit included in asteering and manoeuvering system according to a first embodiment;

FIG. 1B is a heavily simplified block diagram of the steering andmanoeuvering system in its entirety;

FIG. 1C schematically illustrates a steering control included in asteering and manoeuvering system according to a first embodiment;

FIGS. 2A, 2B and 2C illustrate in a corresponding way a control unit anda steering and manoeuvering system in accordance with a secondembodiment;

FIG. 3 schematically illustrates how the steering and manoeuveringsystem in accordance with the invention functions when sailing in twodifferent special manoeuvering modes (turning and athwartshipsmovement); and

FIG. 4 schematically illustrates how the propulsion power is distributedin the steering and manoeuvering system according to FIGS. 2A, 2B and2C.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A steering and manoeuvering system built up around two conventionalcomponents is illustrated in FIGS. 1A, 1B and 1C, namely a steeringcontrol 1 in the form of a lever for steering a vessel to starboard orport and a double lever control 2 for controlling propulsion power(engine power) and propulsion direction (ahead/astern) of the starboardand port propulsion units. The steering and manoeuvering system can thusbe installed by connection to an existing equipment. In addition, afunction selector is fitted, this being in the form of a preselectionswitch with three buttons 3, 4, 5 for selecting a normal steering mode,a turning mode or an athwartships movement mode. Position sensing meansa, b, c, d (FIG. 1B) are arranged for sensing head or astern positionsof each control lever 2a, 2b.

The steering control 1, the preselection switch 3, 4, 5 and the controllever position sensing means a, b, c, d are connected to an electronicsteering unit 6 provided with logical circuits, and which on its outputside gives control signals to actuating turning units 7, 8 for angularcontrol of the starboard and port propulsion units, respectively. Theseturning units 7, 8 are preferably servo controlled units ofelectromechanical, electrohydraulic or electropneumatic type. The powercontrol 2 is conventionally connected to actuating drive units 9, 10,e.g. by mechanical or hydraulic transmission for acting on thepropulsion power (or engine power) and propulsion direction(ahead/astern) of the respective propulsion unit.

The logical circuits of the steering unit 6 decode the incoming signalsand actuate both turning units 7, 8 so that the turning angle of thepropulsion units correspond to a desired sailing mode and the setting ofthe steering and power controls.

For the NORMAL steering mode (preselection button 3) the vessel issteered and manoeuvered conventionally, the steering control functioningsuch that the propulsion units are kept parallel as they are turned,while the propulsion power and direction of the respective propulsionunit can be set individually with the aid of the power control levers2a, 2b. This steering mode is generally used for movement ahead, asternor simple manoeuvers.

For relatively complicated manoeuvers such as those needed in harbours,tying up to a quay or pier etc., the preselection buttons 4 and 5 areused for switching onto the turning mode or the athwartships mode,respectively. The parallel relationship of the propulsion units causedby the steering control 1 is disengaged in these special manoeuveringmodes, and the steering unit 6 then sets the propulsion units insymmetrical turning angles in opposite directions. A necessaryprerequisite for the effectiveness of these special manoeuvering modesis that the propulsive directions of the propulsion units are mutuallyopposite, i.e. one power lever, e.g. 2a, is set ASTERN and the other,e.g. 2b, at AHEAD.

In the TURNING mode (cf. FIG. 3), both propulsion units are directedtowards a point astern the vessel on the extension of its fore and aftline. When the steering control 1 is set in neutral position (B and H inthe Figure), these turning angles are predetermined by being programmedinto the steering unit 6 and result in that the vessel turns to port(position B) or to starboard (position H) about its centre of gravity inthe lateral plane. In this mode, the steersman can increase or decreasethe rate of turn during the course of manoeuvering by using the levers2a, 2b or adjust the angles of the propulsion units (while maintainingsymmetry) and thereby displace the point of action in the fore and aftdirection with the aid of the steering control 1, see positions A, C, Gand I.

In the ATHWARTSHIPS mode both propulsion units are directed towards thecentre of gravity of the vessel in the lateral plane, when the steeringcontrol 1 is set in the neutral position, see positions E and K. In thiscase the vessel will be moved exclusively athwartships to port orstarboard, provided that wind and current do not cause any torque. Ifthis should be the case, the steersman can apply a compensating torqueby a corresponding setting of the steering control 1, the point ofaction of the force resultant then being displaced fore or aft, seepositions D, F, J and L in FIG. 3.

If the levers 2a, 2b of the power control 2 are in the positions "bothahead", "neutral" or "both stern", (which is sensed by the means a, b, cand d, FIG. 1B), the NORMAL mode is kept engaged, even if one of thebuttons 4 or 5 has been depressed. Preselection of the desired specialmanoeuver mode can thus take place before the intended manoeuver, themode in question being engaged automatically when the force directionsare shifted with the aid of the levers 2a, 2b. However, changing betweenthe turning and athwartships modes can take place without delay bydepressing the respective button 4 and 5 during the manoeuver inprogress. Similarly, the NORMAL mode is reengaged as soon as the button3 is depressed.

In the steering system according to FIGS. 2A, 2B and 2C there is used aprincipally similar steering control 1 and the same preselector switches3, 4, 5 as in FIG. 1A. However, the power control is formed differentlyand comprises a first lever 2'a for synchronous setting of thepropulsive power (or engine power) ahead/neutral/astern of thepropulsion units, and a second lever 2'b for differential balancing ofthe propulsive powers/directions (starboard/neutral/port) such that,when the lever 2'a is in a neutral position and the lever 2'b is beingswung to port, the propulsive power of the port propulsion unit asternis increased and to a corresponding degree that of the starboardpropulsion unit is increased ahead, and when swinging the lever 2'b tostarboard, the propulsive power of the starboard propulsive unit isincreased astern and that of the port propulsive unit is increased to acorresponding degree ahead. The lever 2'a is then used to adjust theamount of power while maintaining the vectorial difference between thepropulsive powers, ahead or astern, for compensating exterior forcesacting in the fore and aft line of the vessel. Co-action between thelevers 2'a and 2'b and their vectorial effect on power is illustrated inFIG. 4. In FIG. 4, (H) represents that opposing drive directionsactivate preselected special mode (harbor or manoeuvering mode). (L)represents a vector sum greater than 100% (limited to 100%).

It has been found that a power control according to FIG. 2A is verysimple to handle after only a short training course for the personconcerned.

In the NORMAL mode the vessel is steered by the steering control 1, andthe propulsive power lever 2'a functions as a parallel-connected doublelever control, the power balancing lever 2'b achieving increase/decreaseof the power of the respective propulsion unit. When the lever 2'b isset in the neutral position, the power on both units is in mutualbalance over the entire domain ahead-neural-aster for the lever 2'a.Consequently, the NORMAL mode is retained engaged, even when one of thebuttons 4, 5 is depressed.

The preselected special manoeuvering mode is enabled as soon as thelever 2'b is moved to port or starboard sufficiently far for onepropulsion unit to propell ahead and the other astern, see the positions(H) in FIG. 4, which corresponds to a double lever control being setwith one propulsion unit in the propulsive direction ahead and the otherone astern. Both propulsion units are now acted on symmetrically, butwith different force directions, when the power is changed by the lever2'b towards the desired side for athwartships or turning movement.

The steering control 1 can also be utilized in this case for fineadjustment of the point of action of the force resultant in the TURNINGor ATHWARTSHIPS modes, as illustrated in FIG. 3. In addition, somepropulsive power can be superposed ahead or astern with the aid of thepropulsive power lever 2'a for compensating current or wind action inthe fore and aft direction of the vessel. The steering and manoeuveringsystem otherwise functions in a corresponding manner as in the precedingembodiment.

In this case, however, all transmission from the steering control 1,preselector switches 3, 4, 5 and the power control 2' takes place via acentral electronic steering unit 6', which controls the two actuatingturning units 7', 9' as well as the two actuating drive units 8', 10'for the starboard and port propulsion units. For reasons of safety anemergency system (a so-called back-up-system) with simple individualcontrol means and indicators can also be connected for direct control ofthe actuating turning and drive units 7'-10'.

The steering and manoeuvering system can be modified by one skilled inthe art in many ways within the scope of the following claims. Forexample, the levers 2'a and 2'b may be replaced by a single lever of thejoystick type, which is movable in two dimensions. In addition, it maybe sufficient with only one special manoeuvering mode, e.g. TURNING,ATHWARTSHIPS or a combined TURNING/ATHWARTSHIPS mode. Alternatively,three or more special manoeuvering modes can be used. The steeringcontrol 1 can be replaced by a wheel. The conditions for initiating apreselected sailing mode can be varied as desired. Finally, preadjustingmeans can be arranged, suitably placed near the control unit forindividually adjusting the ATHWARTSHIPS and TURNING modes, so that thepresetting of the turning angles of the propulsion units give thedesired effect in the respective special mode (when the steering controlis in a neutral position).

I claim:
 1. Steering and manoeuvering system for water-born vessels withtwo individually turnable propulsion units arranged at the stern portionof the vessel and mutually spaced athwartships, includingan actuatingturning device for controlling the turning angles of the two propulsionunits such that they remain mutually parallel in a normal steering modeof the vessel, wherein the vessel is moving ahead or astern, saidturning device being actuable by a steering control, and an actuatingdrive device for setting the propulsive power and direction ahead/asternof the respective propulsion unit, said drive device being actuable by apower control, characterized in that the steering and manoeuveringsystem includes a function selector with the aid of which the system isswitchable between said normal steering mode, and at least one specialmanoeuvering mode, where the steering control is disconnected from itsnormal steering function where the propulsion units are kept parallel,and said actuating turning device is instead actuated automaticallyirrespective of the position of the steering control for setting the twopropulsion units at symmetrical turning angles in opposite directions sothat the two propulsion units achieve a force resultant directedsubstantially athwartships, while said actuating drive device isactuated for setting the two propulsion units in opposing propulsivedirections ahead/astern; and in that the steering control, in said atleast one manoeuvering mode, actuates said actuating turning device suchthat the turning angles are changed symmetrically in oppositedirections, whereby the point of action of the force resultant isdisplaced along the vessel's fore and aft line, including the linearextensions thereof.
 2. Steering and manoeuvering system as claimed inclaim 1, characterized in that said at least one special manoeuveringmode includes the following manoeuvering possibilities;an athwartshipsmovement of the vessel parallel to itself to starboard or port, bothpropulsion units being kept directed towards the centre of gravity ofthe vessel in the lateral plane and, in case of outside forcesattempting to turn the vessel, towards a point displaced from saidcentre of gravity along said fore and aft line for compensating saidoutside forces and a clockwise or anti-clockwise turning of the vesselabout said centre of gravity, wherein both propulsion units are keptdirected towards a point astern situated on the extension of the foreand aft line of the vessel.
 3. Steering system as claimed in claim 2,characterizedin that, during said athwartships movement of the vessel,movement of the steering control to starboard achieves displacement ofsaid point of action astern (E-F), when the vessel is moved athwartshipsto port, and ahead (K-L), when the vessel is moved athwartships tostarboard, while movement of the steering control to port achievesdisplacement of said point of action ahead (E-D), when the vessel ismoved athwartships to port, and astern (K-J), when the vessel is movedathwartships to starboard, and in that, during said turning movement ofthe vessel, a movement of the steering control to starboard achievesdisplacement of said point of action astern (B-C), when the vessel isturned anti-clockwise, and ahead (H-I), when the vessel is turnedclockwise, while a movement of the steering control to port achieves adisplacement of said point of action ahead (B-A), when the vessel isturned anti-clockwise, and astern (H-G), when the vessel is turnedclockwise.
 4. Steering and manoeuvering system as claimed in claim 3,characterized in that the function selector is a preselector switchwhich does not achieve switching to the set function until certainoperational conditions are complied with.
 5. Steering and manoeuveringsystem as claimed in claim 4, characterized in that, in said at leastone special manoeuvering mode, the mutual relative positions of thepower control levers determine whether the movement takes place tostarboard or port.
 6. Steering and manoeuvering system as claimed inclaim 4, characterized in that said steering control, said functionselector and said position sensing means are connected to a steeringunit which actuates said actuating turning device, whereas said powercontrol is connected to said actuating drive device without theintermediary of said steering unit.
 7. Steering and manoeuvering systemas claimed in claim 6, characterized in that the power control includestwo separate levers, one for each of said dimensions.
 8. Steering andmanoeuvering system as claimed in claim 6, characterized in that anecessary condition for switching from said normal steering mode to aspecial manoeuvering mode is that the power control is set such that onepropulsion unit is propulsive ahead and the other astern.
 9. Steeringand manoeuvering system as claimed in claim 4, characterized in thatsaid steering control, said function selector and said power control areconnected to a steering unit which controls said actuating turningdevice as well as said actuating drive device.
 10. Steering andmanoeuvering system as claimed in claim 1, characterized in that thefunction selector is manually settable for selecting any one of saidnormal steering mode and said at least one special manoeuvering mode.11. Steering and manoeuvering system as claimed in claim 1, wherein saidpower control is constituted by a conventional combined control with twoparallel, movable levers adjacent each other, each of which is connectedto a respective propulsion unit, characterized in that position sensingmeans are arranged for sensing the ahead or astern position of eachlever, and in that a necessary condition for switching from said normalsteering mode to said at least one special manoeuvering mode is that onelever assumes a position of ahead and the other lever assumes a positionof astern.
 12. Steering and manoeuvering system as claimed in claim 1,characterized in that the power control is settable in two dimensions,namely in a first dimension for synchronous setting of the propulsivepower ahead/neutral/astern of both propulsion units and in a seconddimension for differential power balancing starboard/neutral/portbetween the two propulsion units.